Sending a user to gift an app from inside an app doesn't work anymore?

Up until a few days ago, the following URL handler to redirect a user for gifting an app worked:

  static NSString * const kAppStoreGiftURL = @"itms-appss://buy.itunes.apple.com/"
  "WebObjects/MZFinance.woa/wa/giftSongsWizard"
  "?gift=1&salableAdamId=%u&productType=C&pricingParameter=STDQ&mt=8&ign-mscache=1";

  NSString *url = [NSString stringWithFormat:kAppStoreGiftURL, kAppID];
  NSLog(@"Opening store with URL: %@", url);
  [[UIApplication sharedApplication] openURL:[NSURL URLWithString:url]];

However, it seems that right now this yields the following error message after openURL:

Gifting an app directly via the store is still available.

Did Apple disable this feature completely, or is there a new URL that mitigates this issue?